1. Field of the Invention
This invention is directed toward an improved detachable saw tooth adapted to be mounted on a circular saw disk.
The invention is more particularly directed toward an improved detachable saw tooth of the type that has a plurality of cutting edges. A tooth having a plurality of cutting edges can be repositioned in its mounting on the saw disk to present a sharp cutting edge when the edge currently in use becomes dull.
2. Description of the Prior Art
The saw tooth having a plurality of cutting edges usually has a four-sided main body with a mounting end and a cutting end. The cutting end usually has a concave, part-spherical surface which intersects with the straight sides of the body to form four concavely curved cutting edges. A tooth of this type is shown in U.S. Pat. No. 4,937,447, Morin, issued Jun. 12, 1990. The tooth is mounted, on one side of the body, on a holder that in turn is mounted on the rim of a circular saw disk. All the cutting edges face in the direction of rotation of the tooth but only the outermost cutting edge cuts as the disk rotates. When this cutting edge dulls the tooth can be rotated 90.degree. or 180.degree. in the holder to present a fresh cutting edge. With the tooth having four cutting edges, it has quite a long life before it has to be removed for sharpening or replacement.
However the tooth presents some problems. The curved cutting edges, which meet at relatively sharp corners, tend to have a ripping action when cutting, making it relatively inefficient. In addition, it is quite time consuming to have to rotate all the teeth on the saw disk when the cutting edges become dull. The time between tooth rotations could obviously be increased by making the teeth of harder material or by using hardened inserts to provide the cutting edges. However since the cutting edges are curved, the cost of machining or otherwise forming these hardened teeth or inserts greatly increases making the longer-life teeth very expensive and thus not really any cheaper in the long run.